The present invention relates to a swivel joint and, more particularly, to a swivel joint having stepped bearing races.
Swivel joints are used in connect fluid pipes in oilfields and in other applications. Swivel joints are generally comprised of interfitting male and female members rotatably connected by a bearing assembly. Typically, inner and outer grooves are incorporated in the male and female members to form a bearing race, and a plurality of ball bearings are housed within the race. Higher demand for compatibility with increased service pressure, wider operating temperature range, and a greater variety of corrosive chemicals has resulted in swivel joint designs with multiple bearing races rather than one bearing race. Even with multiple bearing races high pressures can sometimes cause deformation or brinelling of the bearing races. Such brinelling relaxes the compression of the seal between the male and female members and causes the seal to leak, preventing the swivel joint from swiveling smoothly under pressure and reducing the bearing race life significantly. In addition, errosive wear in the male member under the bearing race can quickly reduce the integrity of the swivel joint.